This invention relates generally to the working of hard and brittle materials and more particularly to an apparatus or machine for cutting workpieces of hard materials such as glass and ceramic.
In general, a hard workpiece such as a glass or ceramic plate has heretofore been cut by a process which comprises first forming an incised line or fine groove conforming to the shape to be cut on one surface of the workpiece by means of a cutting tool such as a diamond point cutter, grasping with two hands the edges of the workpiece on opposite sides of the incised line, and applying a bending moment to the workpiece along the incised line, thereby to causing the workpiece to fracture along the incised line.
By this known cutting technique depending on directly applied bending stress, relatively thin workpieces or materials can be easily cut, but in the case of large workpieces, particularly thick plates, for example, glass plates of 15-mm thickness or more, problems such as extreme difficulty or near impossibility of the cutting operation are encountered.